Vortex Magnetoresistor Multi-Axis Sensing and Noise Reduction
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Solution Overview
Problem
Conventional magnetic field sensing devices face challenges in achieving high accuracy due to flicker noise interference and increased manufacturing costs associated with multi-axis sensing, which limits their reliability and efficiency.
Innovation Solution
The magnetic field sensing device incorporates a vortex magnetoresistor with a round free layer having a vortex-shaped magnetization direction distribution and a magnetization setting element that alternately applies electric current to destroy this distribution, allowing for effective sensing of external magnetic fields while mitigating flicker noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple magnetoresistors with different pinning directions are used to achieve multi-axis sensing, then the sensing capability in multiple directions is improved, but the manufacturing cost increases significantly and the stability of magnetization direction configuration deteriorates
Solution Approach 1:
The patent uses a single vortex magnetoresistor structure that can sense magnetic fields in multiple directions by utilizing the vortex-shaped magnetization distribution in the free layer. The vortex core can be oriented in different directions to achieve multi-axis sensing without requiring multiple separate magnetoresistors with different pinning directions, thus reducing manufacturing complexity and cost while maintaining multi-directional sensing capability.
Solution Approach 2:
The patent changes the magnetization distribution parameter from conventional uniform magnetization to vortex-shaped magnetization in the free layer. This parameter change allows the single magnetoresistor to respond to magnetic fields in multiple directions by detecting changes in the vortex core position or magnetization configuration, thereby achieving multi-axis sensing without the need for multiple devices with different pinning directions.
2Reliability
If conventional magnetoresistors are used, then the basic magnetic field sensing function is achieved, but flicker noise interferes with the accuracy of magnetic field strength measurement
Solution Approach 1:
The patent converts the harmful effect of flicker noise by using the vortex magnetoresistor's unique magnetization characteristics. The vortex-shaped magnetization distribution in the free layer provides a different noise profile and signal response compared to conventional magnetoresistors. By utilizing the vortex core's sensitivity to magnetic field changes and its distinct electrical resistance characteristics, the patent achieves better signal-to-noise ratio and measurement precision while maintaining reliable sensing function.
3Device complexity
If a single-axis magnetic sensor with Wheatstone bridge is used, then the structure is simple, but it can only sense magnetic fields in one direction and requires multiple devices for multi-axis sensing
Solution Approach 1:
The vortex magnetoresistor is designed to perform multiple sensing functions within a single device structure. By controlling the vortex core orientation and utilizing the magnetization distribution characteristics, the single magnetoresistor can detect magnetic field components in multiple directions, effectively replacing what would traditionally require multiple separate sensors while maintaining structural simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances the device's ability to accurately sense external magnetic fields by reducing the limitations on magnetic field direction sensing and effectively subtracting flicker noise interference, resulting in improved accuracy and reliability.
Implementation Method 1
When the at least one magnetization setting element is applied the electric current to, a magnetic field generated by the at least one magnetization setting element destroys the magnetization direction distribution with the vortex shape of the round free layer and makes the round free layer achieve magnetic saturation
Implementation Method 2
When the at least one magnetization setting element is not applied the electric current to, the magnetization direction distribution with the vortex shape of the round free layer is varied with an external magnetic field to sense the external magnetic field
Data Source
AI summary
A magnetic field sensing device includes at least one vortex magnetoresistor and at least one magnetization setting element. The vortex magnetoresistor includes a pinning layer, a pinned layer, a spacer layer, and a round free layer. The pinned layer is disposed on the pinning layer, and the spacer layer is disposed on the pinned layer. The round free layer is disposed on the spacer layer, and has a magnetization direction distribution with a vortex shape. The magnetization setting element is alternately applied and not applied an electric current to. When the magnetization setting element is not applied the electric current to, the magnetization direction distribution with the vortex shape of the round free layer is varied with an external magnetic field. When the magnetization setting element is applied the electric current to, a magnetic field generated by the magnetization setting element makes the round free layer achieve magnetic saturation.